1. Field of the Invention
The present invention is generally concerned with the assembly comprising a clutch and the clutch release bearing required to control it.
It is more particularly directed towards the case where, in order to release the clutch, the clutch release bearing must act in traction on the clutch release device which the clutch comprises for this purpose.
The problem in this instance is that, although necessarily disposed for the main part outside the clutch, the clutch release bearing must nevertheless be able to act within the latter, on the internal surface of the clutch release device, so as to be capable of exerting traction on it.
2. Description of the Prior Art
To overcome this difficulty, it is usual to couple the clutch release bearing to the clutch release device in at least one axial direction, being that corresponding to traction on the clutch release device.
More precisely, for the purposes of such coupling of the clutch release bearing to the clutch release device, it is usual to associate with the latter an ancillary member, referred to hereinafter for convenience as the coupling member, which, on the side of the clutch release device opposite the clutch release bearing, has a radial flange through the intermediary of which it is adapted to bear on the clutch release device in the required axial direction.
It then remains to couple together the coupling member and the clutch release bearing in at least this direction, corresponding to traction on the clutch release device.
Various arrangements of differing complexity have been proposed to this end.
The simplest consists in the use, on the side of the coupling member opposite the clutch release bearing, of a ring referred to hereinafter for convenience as the coupling ring which is elastically deformable in the radial direction, extends annularly around the axis of the assembly and is at least in part engaged, on the one hand, on the same side as the clutch release bearing, with a bearing surface of the coupling member and, on the other hand, on the opposite side, with a bearing surface of the clutch release bearing.
At present, a ring of this kind is more often than not a simple split ring and has no function other than to provide the necessary axial coupling between the clutch release bearing and the coupling member.
As a result, it more often than not the case that the clutch release bearing must be fitted to the clutch release device of the clutch which it is to control in advance, even before the fitting of the latter, this fitting normally preventing subsequent fitting of the coupling ring within the device.
In other words, at present the clutch release bearing must normally be fitted in advance to the "clutch cover assembly" of a clutch of this kind.
In this context, as is usual, the term "clutch cover assembly" designates the assembly of the component parts of a clutch which, as a unit and inclusive of the clutch release device, are mounted on a reaction plate, or flywheel, with a friction disk inserted between them, to constitute a clutch of this kind.
The fact that a clutch release bearing which must operate in traction is fitted in advance to a clutch cover assembly of this kind complicates the assembly, and makes handling and packaging difficult, the clutch release bearing producing an unwanted increase in the overall axial dimension of the assembly during such handling and packaging.
Also, problems result during the joining together of the motor concerned and the corresponding gearbox, the casing of the latter normally being fitted in advance with the clutch release yoke which is needed to control the clutch release bearing and this clutch release yoke needing to be engaged on said clutch release bearing as the motor and the gearbox are brought axially towards one another for the purpose of fastening them together.
To overcome these problems it has been proposed to use snap-fastener means to provide the required axial coupling between the clutch release bearing and the coupling member for it provided on the clutch release device of the clutch to be controlled.
By virtue of such snap-fastener means, the clutch release bearing, which is in this case commonly referred to as of the "clip-on" type, can be fitted after the clutch release bearing itself has already been fitted to the corresponding reaction plate.
All that is necessary is to insert the clutch release bearing axially into the central opening in the clutch release device of the clutch cover assembly: during such insertion, the snap-fastener means employed retract elastically and, on subsequently resuming their initial configuration, provide the necessary axial retaining action.
Snap-fastener means of this kind may be fitted to the clutch release bearing.
They may also be fitted to the coupling member.
This is the case, in particular, in French patent application No. 81 22108 filed Nov. 20, 1981 and subsequently published under the number 2 494 796, in which they consist of a ring.
In all cases, it is also necessary to use retaining means adapted to axially couple to the clutch release device the coupling member associated with the latter, failing the provision of which, on engagement of the clutch release bearing, the coupling member would be entrained by the latter in the axial direction, without the required snap-fastener action being obtained.
In certain arrangements already known in the art, these retaining means form an integral part of the coupling member.
As an alternative, they may form a separate part.
This is the case, in particular, in French patent application No. 81 22108, in which they comprise a special ring.
In an arrangement of this kind, three separate parts are necessary to couple the clutch release bearing to the clutch release device to be controlled, namely the coupling member, the ring constituting the retaining means for the latter, and the ring providing for the snap-fastener type attachment of the clutch release bearing to the latter.
A general objective of the present invention is an arrangement whereby the number of parts required may be reduced.